Determination of Lead,Chromium(Ⅵ),Cadmium and Mercury in ABS Plastics

ABS plastics sample was digested with a mixed acid of conc.H2SO4 and conc.HNO3 (mixed in the ratio of 1 to 5).Lead(Ⅱ) was precipitated as PbSO4 during the sample digestion and its was dissolved in NH4OAc and determined by FAAS in an acetate buffer solution with a detection limit of 0.088 mg·L-1.Cadmium(Ⅱ) in the solution was also determined by FAAS with a detection limit of 0.074 mg·L-1.Mercury(Ⅱ) was determined by the hydride generation-cold-vapour atomic absorption spectrometry.The detection limit of mercury(Ⅱ) was found to be 0.64 μg·L-1.Hexavalent chromium in the sample solution was determined by photometry using diphenylcarbazide as color reagent.Detection limit of Cr(Ⅵ) found was 0.039 mg·L-1.Precision and recovery of these methods were tested giving values of RSD′s (n=7) less than 3.5%,and of recovery in the range of 91.8%-106.0%.